MILWAUKEE (AP) — The Milwaukee Bucks fired Adrian Griffin as coach on Tuesday after just 43 games despite having one of the league’s top records midway through his first season.

“This was a difficult decision to make during the season,” Bucks general manager Jon Horst said in a statement announcing the move. “We are working immediately toward hiring our next head coach. We thank Coach Griffin for his hard work and contributions to the team.”

Joe Prunty, who had been an assistant coach on Griffin’s staff, will serve as the Bucks’ interim head coach. Horst will speak at a news conference Wednesday, before the Bucks’ home game with the Cleveland Cavaliers.

Milwaukee is 30-13 to tie the Minnesota Timberwolves for the league’s second-best record entering Tuesday. The Bucks are 3 1/2 games behind the Boston Celtics in the Eastern Conference.

But the dip in Milwaukee’s defensive performance had raised concerns about the Bucks’ viability as a championship contender even after they had acquired seven-time all-NBA guard Damian Lillard before the season to team up with two-time MVP Giannis Antetokounmpo. The Bucks rank 22nd in the NBA in defensive rating, down from fourth a year earlier.

Milwaukee had given Griffin his first head coaching job this summer after firing Mike Budenholzer, who led the Bucks in 2021 to their first title in half a century. The coaching change came after the top-seeded Bucks were stunned 4-1 by the Miami Heat in the first round of last season’s playoffs.

Griffin, 49, had spent 16 seasons as an NBA assistant, including the last five with the Toronto Raptors. That followed a nine-year NBA playing career.

Taking over a team with two members of the NBA’s 75th anniversary team in Antetokounmpo and Lillard put Griffin under a major spotlight at the beginning of his head coaching career. An early warning sign regarding Griffin’s tenure came before the season with the abrupt departure of assistant coach Terry Stotts.

Stotts had more than 1,000 games of head coaching experience, which figured to benefit Griffin as he began his own head coaching career. Stotts had called accepting the assignment a “no-brainer,” but he left the staff less than a week before the season opener.